advisor vs expert

advisor

noun
  • One who offers advice. 

  • A xiangqi piece, that is moved one point diagonally and confined within the palace. 

expert

noun
  • A person with extensive knowledge or ability in a given subject. 

  • A player ranking just below master. 

adj
  • Extraordinarily capable or knowledgeable. 

  • Characteristic of an expert. 

How often have the words advisor and expert occurred in a corpus of books? (source: Google Ngram Viewer )